More than 68,000 pounds of bagged fresh spinach are being recalled by a Monterey County grower after routine testing found salmonella in a sample taken from a Watsonville packing plant.

There have been no reports of illness from the spinach, but state and federal health officials said they are working with Metz Fresh of King City to determine the source and scope of contamination.

The recall announced Wednesday comes almost exactly one year after a nationwide outbreak of illness was traced to a batch of bagged California spinach that was tainted with a deadly strain of E. coli bacteria.

Since then, produce growers and distributors say they have taken steps to improve sanitation and testing procedures.

The current recall involves a batch of spinach that was packed on Aug. 22 and distributed late last week to retail and food-service customers, such as restaurants or institutional kitchens, in the United States and Canada.

The salmonella was found during testing at a packing plant that was operating under contract with Metz Fresh, said Greg Larsen, a company spokesman.

In a statement, Metz Fresh said the salmonella was detected in a single sample of spinach at the processing plant. The company said it decided to recall spinach from three processing lines at the plant as a precaution, since all three lines were handling produce from the same field.

Company officials began contacting their customers, asking them not to serve or sell the spinach to consumers, after receiving a preliminary test result on Friday, Larsen said. As of Friday night, he added, "we had corralled and held 90 percent of the expanded lot in question."

The company decided to formally recall the product on Tuesday, after lab analysis confirmed the preliminary finding of salmonella.

Officials are still trying to determine whether any of the spinach was sold or served to consumers.

Salmonella can cause fever, abdominal cramps and diarrhea. It can be life-threatening to children, the elderly and adults with compromised immune systems.

The recall involves only fresh spinach packed under the Metz Fresh label, in packaging marked with tracking code 12208114, 12208214 or 12208314. The spinach was packed in 10- and 16-ounce bags, as well as 4- and 10-pound cartons.

Metz Fresh said consumers should discard the spinach or return it to their retailer for a refund. Consumers with questions can call (831) 386-1018.